Escapism is defined as the attempt to avoid awareness of aversive beliefs. Strategies, and a few examples, of escapism are discussed. It is argued that self-deception is one species of escapism and that entrenched escapism, escapism pursued with the intention of permanently avoiding any awareness of one's belief, no matter what happens, is theoretically irrational, except in the special case where it compensates for irrationality elsewhere, by guarding one from the formation of further irrational beliefs of more serious import than the belief one wishes to avoid. The model of rationality employed in this argument is then extended to practical rationality, and it is argued that entrenched escapism is pragmatically irrational as well, unless it compensates for other irrationalities elsewhere in a person, as, for instance, when a person must avoid certain facts to avoid succumbing irrationally to despair, or unless it compensates for the effects of an environment in which it is otherwise impossible for an optimally functioning person to survive emotionally. The results for entrenched escapism would apply to self-deception as well, since it aims (in all but very odd cases) at the permanent removal of the offending belief. The function of escapism, then, is to compensate for irrational patterns of belief formation, and to maintain effectiveness (for the sake of continuance of the species), insofar as that is possible, in situation in which a rational person would succumb to despair and suicide.